Portable drilling machine



May 28, 1935. K. H. ANDREN 2,002,727

PORTABLE DRILLING MACHINE Filed April 9, 1932 9 Sheets-Sheet l IN VEN TOR ATTORNEY-3v y 1935- K. H. ANDREN PdRTABLE DRILLING MACHINE 9 sheetsfiShegt- 2 Filed April 9, 1952 ATTORNEY.

K. H. ANDREN 2,002,727

Filed April 9, 1932 9 Sheets-Sheet 3 PORTABLE DRILLING MACHINE May 28, 1935.

INVENTOR.

' ATTORNEY'.

M y. 8, 1935. K. H. ANDREN 2,002,727

PORTABLE DRILLING MACHINE Filed April 9, 1932 9 Sheets-Sheet 4 INVENTOR.

34) 4/ ATTORNEY'.

May 28, 1935. K. H. ANDREN v PORTABLE DRILLING MACHINE 9 Sheets-Sheet 5 IL I 00 7 a L 8 a 8 3 I W u \QPE. 6 8 7 .w w m I 4 3 2? ll 0 9 Z 6 l a 6 8 2 6/5 4' 3 I 4 7 7 w s 6 5 M a 5 8 6. 4 L J 2 x 9 ATTORNEY y 3 ,K. H. ANDREN j I 2,002,727

PORTABLE DRILLING MACHINE ATTORNEY.

Y y 1935. K. H. ANDREN PORTABLE DRILLING MACHINE Filed April 9, 1932 lb IVENTOR.

ATTORNEY.

M 7 J. I 9 i W 4 a Z I =EE= 3 4 x 4 7 0 :2 5 a w Jim 9 A Ll l l k lllW k 0 .4. 4

I who 8 3 w m2 M H "W Patented May 28, 1935 UNITED STAT-ES PORTABLEDRILLING MACHINE Karl H. Andren, Milwaukee, Wis., assignor to Artos Engineering Company, Milwaukee, Wis., a corporation of Wisconsin Application April 9, 1932, Serial No. 604,169

16 Claims.

The present invention relates in general to improvements in the art of assembling composite structures formed of elements such'as metal plates and bars, and relates more specifically to improved apparatus for producing rivet holes alinement after loose-assembly of the member.

had been effected and preparatory to final riveting. In large or relatively complex structural members of this type, it has always been difficult to insure correct disposition of the rivet holes so as to avoid excessive reaming and alining of the holes during final assembly of the structures. Such reaming is not only costly, but also prevents production of properly located holes having uniform and desired diameter. The assembly of such beam or girder structures with the prior art methods, has therefore been expensive, slow and inaccurate, and the final strucf tures were imperfect.

It is an object of the present invention to provide an improved method of and apparatus for simplifying the mode of assembling structural steel or other composite members, by the provision of simple and highly 'efficient means forproducing properly positioned rivet holes of uniform and accurate diameter, without necessity of reaming such as was previously required. Another object of the invention is to provide improved mechanism for suspending and forpositioning a perforating machine such as'a drill press, so that the machine may be readily conveyed throughout quite an extended area of 011- oration, and readily manipulated to produce holes at any desired angle in various portions of a relatively complex structure.

A further object of the invention is to provide a combined perforator and Work clamp, which can be readily adjusted t'o'diiferent positions relative to the work, and which can be easily manipulated to clamp various portions of a laminated or other composite structure into intimate contact with each other. v j

Still another object of the invention is to provide improved means for eliminating necessity of either furnishing a specially constructed I, rigid and costly support for" a perforating machine such as a drill or punch press, or providing such a support for the structure to be perforated and assembled.

, Another object of the invention is to provide an improved perforating machine such as a punch or drill press, which is especially adapted to produce alined holes in a series of laminations or plates coacting with each other. A l

A further object of the invention is to pro vide a portable perforator unit such as a drill press-which is clamped into operative position upon the work, rather than having the-work supported by or clamped to the perforating machine itself, whereby large pieces of work can be convenicntly perforated with minimum effort by vir tue of the lightness, compactness and convenient, portability of. the perforating unit.

Still another object of the invention isto provide improvedclamping means for holding layers of material in firm coaction with each other.

and for preventing separation of the layers, so that chips or other foreign matter cannot get between the laminations during the perforating operation.

Another object of the inventionis to provide an improved clamp for holding a portable perforating machine so as to positively position the work at the proper angle, usually perpendicular, relative to the direction of movement of the perfoe rating tool.

A further object of theinvention is to provide an improved clamping media which is adapted to effectively resist twisting or angular displacement of the work about the. axis of travel of the perforating tool, such as is induced by the torque in a rotary perforator or drill operated by a portable prime mover; 1

Still another object of the invention is to providemeans for quickly and effectively manipulating work clamping mechanism, and for efi'ecting abnormal opening of the clamping. jaws so as to permit convenient application, shifting and removal of the mechanismt Another object of the invention is to provide improved mechanism for eiiecting either automatic or manual clamping and release of the Work, and similar interchangeable operation or withdrawal of the perforating tool of a machine.

A further object of the invention is to provide an improved toe clamp structure or clamp rail mounting for effecting utilization and movement of a perforating machine in conjunction witha flat object or piece of work.

Still another object of the invention is to provide improved instrumentalities for effecting variation in the direction or extent of the perforations, and of the elfective clamping, without changing the structure of the perforating unit and also without shifting the work.

Another object of the invention is to provide improved means for counter-balancing the weight of a. portable perforator so as to facilitate movement and manipulation thereof.

A fuither object of the invention is to provide an improved movable or swinging suspension cooperating with the center of gravity of a drilling or punching unit, whereby the perforating tool may be conveniently brought into alinement with center punch holes or other marking media.

Still another object of the invention is to provide an improved hinge system for movably suspending a machine, and means for counter-balancing the weight of the machine, wherein the counter-balancing means does not interfere with the free use of the hinged suspension system.

These and other objects and advantages will be clearly apparent'from the following detailed description.

A clear conception of embodiments of the va rious features of the present improvement and of the construction and mode of operation of portable drills 'and clamping devices built in accordance with the invention, may be had by referring to the drawings accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views:

' Fig. 1 is a somewhat diagrammatic side elevation of an improved drill press and of a suspension device therefor, showing the press associated with a laminated member preparatory to drilling horizontal holes through depending flange portions of the member;

- Fig. 2 is a similar view of the drill press showing the same associated with another portion of the laminated member preparatory to the drilling of vertical holes through the member just within the flanged edge thereof, the press being provided with a modified form of clamp;

- Fig. '3 is a similar view of the drill press showing the same associated with an upwardly projecting flange portion of the laminated member preparatory to drilling horizontal holes through said portion with the aid of a clamp similar to that utilized in the assemblage of Fig. 1;

Fig. 4 is a relatively diagrammatic side elevation of the improved drill press, showing the same in use for drilling vertical holes in the medial portion of a laminated member, with the aid of a special clamp;

- Fig. 5 is a front view of the assemblage illustrated in Fig. 4, showing the special clamp more in detail;

'Fig. 6 is an enlarged front view of the improved portabledrill press and of a fragment of an improved clamp of the form shown in Fig. 2;

- Fig. "7 is a similarly enlarged part sectional front view of the drill press, the section being taken along the irregular line ?--'i of Fig. 16;

Fig. 8 is alikewise enlarged central vertical section through the drill press, taken along the line 88 of Fig. 9;

Fig. 9 is a top part sectional viewer" the improved portable drill press, drawn to the same scale as Fig. 6, and with the upper gear case cover removed, the section being taken along the line 9-5 of Fig. 6;

Fig. 10 is a transverse horizontal section through the drill'press, taken along the irregular line llli ll of Fig. 8 and drawn to the same scale;

Fig. 11 is a side view of the improved drill press drawn to the scale of Fig. 6 and looking toward the right of the device as viewed in the latter figure;

Fig. 12 is a fragmentary vertical section through the drill press, taken along the line lZ-EZ of Fig, 9;

Fig. 13 is a fragmentary vertical section through the drill press, taken along the line i3-i3 of Fig. 9;

Fig. 14 is a fragmentary horizontal section through the drill press, taken on the line i i-M of Fig. 7;

Fig. 15 is a fragmentary vertical section through the drill press, taken on the line l5i5 of Fig. 14;

Fig. 16 is a further enlarged fragmentary part sectional top View of the control valve and actuating mechanism for the improved portable drill press;

Fig. 1'7 is a similarly enlarged vertical section through a portion of the control valve and actuating mechanism, the section being taken along the line i'i--ll of Fig. 16;

Fig. 18 is another similarly enlarged vertical section through the control-valve and actuating mechanism, taken on the irregular line iii-i8 of Fig. 16;

Fig. 19 is still another likewise enlarged vertical section through a fragment of the control valve and actuating mechanism, taken along the line i9-l of Fig. 16;

Fig. 20 is a similarly enlarged horizontal section of a fragment of the control valve mechanism, taken on the line 2il2ii of Fig. 17;

Fig. 21 is a diagram showing the drill press control valves in one operative position for vertical drilling, with the spindle balanced prior to application of the power and with clamp released;

Fig. 22 is another diagram of the control valves, showing the same in position corresponding to clamping preparatory to drilling and with the drill spindle being driven;

Fig. 23 is still another diagrammatic disclosure of the control valves positioned to maintain the clamp closed and with the drill spindle ready for withdrawal directly after completion of a hole;

Fig. 24 is a further diagrammatic showing of the control valves at the time the drill leaves the hole and just prior to release of the clamp;

Fig. 25 is a similar showing of the control valves during release of the clamp and with drill spindle disengaged from the advancing mechanism;

Fig. 26 is a diagram of the valve for controlling the balancing cylinder, showing the port arrangement for horizontal drilling;

Fig. 27 is a diagram of the balancing cylinder;

Fig. 28 is a diagram of the clutch control cylinder; and

Fig. 29 is a diagram of the clamp actuating cylinder.

Referring specifically to Figs. 1 to 5 inclusive, it

will be apparent that the present invention com- A prises in general an improved portable power driven drilling unit 38 which is angularly adjustably mounted upon a carrier member or yoke 3i forming a part of the unit; a clamping device detachably associated with the drill unit 33 near the tool supporting spindle of the latter; vertically movable flexible suspension means coacting directly with the carrier yoke 3i; laterally adjustable supporting means 33 for the suspension means 32; and means f r supplying fluid under pressure such astair, to a plurality of actuating valves and cylinders forming part of the drill press or unit 33. The. drill press or unit 30 will be described in detail in conjunction with Figs. 6 to 29, and the means for supplying compressed air or the like to the unit 33, may consist of flexible tubes of usual form communicating with a storage supply tank (not shown). Depending upon the specific use to which the apparatus is to be put, the clamping device or mechanism will assume either of three different forms.

As shown in Figs. 1 and 3, for horizontal drilling of flanged edged portions of a laminated meniber or beam 34, the clamp comprises a rigid reach arm movably supported upon the drill unit 33 for sliding movement parallel to the axis of the drill spindle and carrying one or more reaction elements 36 which are adjustable longitudinally of the spindle axis, and a series of three legs 31, 38 adjustably associated with a clamp bracket 33 which is detachably secured to drill unit frame concentric with the drill carrying spindle. The mechanism for supporting and for effecting sliding movement of the clamp arm 35 will be subsequently more fully described, and the reaction elements 36 should preferably be so formed and disposed that they will not interfere with the passage of a drill through the laminations of .a beam 34 being perforated. The legs 37 which are located in front and in back of the drill to, have plain ends for engaging the beam 34, but the third leg 38 of the tripod, has an end roller 4| cooperable directly withthe beam 34. The legs 31, 38 obviously coact with the side of the beam 34 on which the drill unit 30 is disposed, while the elements 36 react against the opposite side of the beam and within the zone of action of the legs 37, 38 and drill 40, so that when the clamp arm 35 is moved toward the drill unit 33, the elements 36 cooperate with the legs 3?, 38 to firmly clamp the intervening laminations of the beam 34 together. The adjustability of the elements35 and-legs 31, 38 will permit use of the clamp with beams 34;of various thicknesses and comprising a varied number of laminations.

As illustrated in Fig. 2, for vertical drilling of portions of the member or beam 34 within a limited distance from the opposite flanged edges thereof, the clamp comprises an upper arm 42 and a lower arm 43 connected to the upper arm 42 by means of a link 44., and a tripod having legs 3?, 38 identical with those previously described both in, structure and mode of mounting. The upper arm 42 is again movably supported upon the drill unit 33 for sliding movement parallel to the axis of movement of the drill 40, and the lower arm 43 also carries one or more reaction elements 33 which are adjustable longitudinally of the drill axis. The clamp arms 42, 43 are relatively flexible and extend beyond the pivots which connect these arms to the ends of the link 44. A strut 45 is pivotally attached to the projecting end. of the upper arm 42 and normally coacts with the projecting end of the lower arm 43 as shown in full lines in Fig. 2, but when the clamping pressure has been released, the strut 45 may be swung out of contact with the lower arm 43 to thereby permit the lower arm to drop to the. position shown in dot and dash'lines. The clamp may then be moved freely over the flanged edge of the beam 34, or the drilling unit 30 may then be elevated entirely away from the beam Without interference by the clamp arm 43. As in the case i of, the horizontal clamp disclosed in Figs. 1 and- 3,

the vertical edge clamp of Fig. 2 has the tripod legs 31, 38 disposed on the drill side of the beam 34 while the reaction elements 36 are located on the opposite side thereof within the zone of ac tion of the legs 3?, 38 and drill 43, so that movement of the lower arm 43 towardthe drill unit 33 will eifect firm clamping of the intervening laminations. This modified clamp may likewise be adjusted to accommodate beams 34 of various thicknesses, and additionally provides for free removal from the work by virtue of the removable strut 45.

While the clamps shown in Figs. 1, 2 and. 3 are well adapted for use when perforating edge portions of a member or beam 34, they cannot be eifectively utilized when forming holes in medial portions of wide beams 34, remote from the beam edges. For such use, a clamp of the form illustrated in Figs. 4 and 5 may be employed. This special clamp is especially adapted for vertical drilling and comprises a stiff reaction bar 46 which is adapted to be mounted parallel to the drill side of a beam 34 by means of spacing col lars 47 and bolts 48. The bar is secured to the upper overhanging ends of curved press-arms 43 the opposite lower ends of which coact directly with the member or beam 34 and the medial pore tions of which are clamped to the upper ends of the collars 41 by the bolts 43 as clearly indicated in Fig. 5. The holes in the beam 34, with which the clamping bolts 48 coact, may be formed with the aid of a clamp and drill press assembly such as shovm in Fig. 2, and the unit 33 is movablealong the reaction bar 43 to produce a series of parallel holes across the medial portion of the beam 34. The unit 38 of Figs. 4 and 5, is provided with a tripod consisting of a bracket 39 attached to the frame of the unit, and legs 31, 38 adjustably associated with the bracket 39 and engaging the beam 34 at three points around the drill. This unit 33 is also provided with a hook arm 54 whichis movable vertically to produce a clamping effect against the beam 34 at the zone of 'drilling. The hook arm 53 is vertically slidable relative to the frame of the unit 3i! and has an adjustable element 5i cooperable directly with the lower face of the bar 46, and upon release of the clamping pressure, the unit 33 may be slid along the bar 43 while resting upon the roller 4i.

From the foregoing specific descriptions of the of any portion of a laminated member or beam 4 34 may be readily effected.

.The vertically movable flexible suspension means 32 which coacts directly with the carrier yoke 3i of the unit 36, is illustrated in detail in Fig. 1, and comprises a chain 52 ,coacting with a sprocket 53. One end of the sprocket chain is attached to the yolze 3! by means of a swivel 54, and the opposite chain end is secured to a cable. 55 which pass s over and under a series of sheaves 55 and has a counter-balance weight 55 secured to the end thereof remote from the chain 52. balance the weight of the unit 33 and yoke 3|, and'the sprocket 53 is rotatable to: either raise or lower the chain 52, by means of a hand hoist 5! which due to the counterbalancing aflorded by the Weight 56, requires but little effort for operation. With the aid of the suspension means 32 just described, the drilling unit 33 may be conveniently and quickly elevated or lowered as Theweight 38 serves to substantially desired, and subsequently suspended in a definite horizontal plane.

The laterally movable supporting means 33 upon which the suspension means 32 is mounted, is likewise shown in detail in Fig. 1, and comprises a series of pivotally connected brackets 58, 59, til the former of which is swingable relative to a fixed or a traveling support 6!, about a vertical hollow pivot 52. The opposite ends of the intermediate bracket 5%, are swingable relative to the adjacent ends of the end brackets 58, Eli about similar hollow pivots E33, S 3 respectively. The sheaves are rotatably supported by the brackets Ed, 59, 6D so as to guide the vertical portions of the cable 55 in line with the pivotal axes of the brackets, and thus permit the counter-balancing weight 56 to function without interference by the movement of the brackets 58, 5Q, 68 relative to each other. It will be obvious, that by moving the brackets 58, 59, 66 of the supporting means relative to each other and to the support 6! about the vertical pivots 62, 53, i i, the free end of the bracket 6% which carries the unit 89, may be moved to any desired position throughout quite an extended horizontal area, without in any manner interfering with vertical or angular adjustment of the unit 33.

From the foregoing specific description of the suspension mechanisms, it will be apparent that the unit 3% may be universally moved or adjusted, either about its own horizontal axis of suspension, or vertically, or horizontally, throughout a considerable range, thereby permitting cooperation of the unit with any portion of a fixedly supported beam B l of great length and breadth having edge flanges of considerable height and of various angles. This portability of the perforating unit 3%, avoids necessity of moving the relatively heavy piece of work or beam 3:3, and the movement of the drill press is greatly facilitated by the counter-weight 56 which substantially counter-balances the I weight 0-: the portable unit as.

The construction and mode of operation of the improved drilling unit 3f? will be clearly apparout by reference to Figs. 6 to 29 inclusive. This unit Bil comprises in general a main frame 65 which is angularly adjustable relative to its carrier yoke 3i, and provides a support for a rotary axially movable drill spindle 66 and for the spindle driving motor 6?, see Figs. 6, '7, 8 and 11. The frame 65 has a through bore along which a carriage as is slidable, and the spindle 66 which carries a chuck G9 cooperable with drills All of various sizes, is rotatably supported in and is fixed against longitudinal movement relative to the carrier by ball bearings iii mounted in the upper and lower ends of the carrier 68, see Fig. 8. The carriage 68 is longitudinally movable to feed and to withdraw the drill 4E and spindle (it, by means of a pinion 'il coacting with a rack 12 at one side of the carriage, and the carriage 68 is prevented from rotating within its guiding bore by means of a spline l3 cooperating with a groove M formed in the frame 65. The end of the spindle 66 remote from the chuck 69, is longitudinally grooved for sliding coaction with a spur gear 15 which is secured to a rotary bushing 16 mounted in ball bearings Ti supported by a sleeve 18 secured to the upper end of the frame 85, see Figs. 8 and 9. While the gear 15 is freely rotatable about the axis of the spindle 66 so as to impart rotation to the spindle and to the drill 49 associated therewith, this gear is fixed against axial displacement, and meshes with a pinion '59 carried by a-counter shaft 80. The counter shaft 89 is rotatably mounted in ball bearings Si removably supported by the frame 55, and also carries a second pinion 82 which meshes with a spur gear 83 secured to an end of a second counter shaft 84. The second counter shaft fit is rotatably supported in ball bearings 85 carried by the frame 65, and has another spur gear 35 secured to its opposite end and meshing with a driving pinion 8'5. The pinion 81 is driven directly by the driving motor 6'! through the motor shaft 88. The motor iii may be of the electric type, and the speed reducing gears 83, 82 are preferably removable from their supporting shafts so as to permit substitution of other gears therefor, for the purpose of changing the speed of rotation of the spindle 66. In order to facilitate such interchange of gears, the frame is provided with a removable end cover 8%, and a tubular extension 9% within which the grooved driving end of the spindle as is longitudinally movable is also provided, see Fig. 8.

While the main function of the electric motor 6'. is to rotate the spindle 555 and to advance the same for feeding of the drill, other means operable by fiuid such as air under pressure are provided for withdrawing the same upon completion of the drilling operation. This drill spindle balancing and withdrawing means comprises the carrier as and rack '52, and an air actuated servomotor consisting of a cylinder and piston 92 best illustrated in Figs. 7, 8, 10 and 27. The piston 92 is rigidly attached to a rod 93 which is movable parallel to the drill spindle 6t, and the end of which is provided with a rack 95 coacting with the pinion H which also coacts with the rack if of the spindle carrier 68. The rack 96 is movable longitudinally within a hollow clamp guide 95 attached to the main frame 65, and the pinion ii is supported by a shaft 96 journaled in the frame 85 and provided with a hand wheel 97. The pinion H and its supporting shaft 95, are provided with a central bore within which a rod 98 is slidably disposed, and this rod 98 is movable longitudinally by means of a push button 99 located centrally of the hand wheel iii. The shaft 96 also carries a spur gear 588 as shown in Figs. 10 and 12, which meshes with a pinion lei secured to one end of the clutch shaft m2 journaled in the frame 65, and the opposite end of the shaft N32 has a jaw clutch member 503 formed integral therewith. While the shaft IE2 and member 583 are rotatable about the shaft axis, these elements are not movable along the shaft axis.

Disposed coaxial with and adjacent to the end of the shaft 602 remote from the pinion MM, is a short shaft ltd which is rotatably supported in bearings M5, liiii the latter of which is carried within the clutch member N33. The portion of the shaft EM between the bearings H35, 486 is connected by splines to another clutch member In? which is interlockable with the member I03 to produce a positive driving connection between the coaxial shafts lil2, EM. The clutch member IN is constantly rotatable with its supporting shaft w l and is slidable therealong by means of a fork let which is movable by arms Hi9 carried by a pivot shaft I!!! supported on the frame 65 as shown in Figs. 12, 14 and 15. The pivotshaft Mil is rockable by means of a lever Hi the swinging end of which is connected with the plunger rod N2 of a fluid pressure actuated servo-motor, by a link H3. The cylinder H4 'alined shafts I04, I02.

of this clutch actuating servo-motor is mounted in brackets II5 secured to the frame 55, and the servo-motor plunger I I6is secured to the rod II 2 within the cylinder as'shown in Fig. 28. This servo-motor is obviously capable of actuating the jaw clutch consisting of the-members I03, I01 to either drivingly connect, or to disconnect the The clutch actuating servo-motor may be of relatively" small dimensions since but a slight amount of power is re-' quired to move the jaw clutch member I07 into and out of engagement with the member I63, and. the mounting ofthis servo-motor islsuch that it is conveniently accessible from the exterior of the drill or perforating unit 36. p

' Secured to the overhanging end of the shaft I04, remote from the bearing I66, is 3, W01Il'l wheel III which meshes with a worm I58 secured to a shaft H9, and this shaft H3 is also journaled in a housing carried by the frame 65 and carries a pinion I20 which meshes with another pinion I2I secured to one end of a countershaft i22 journaled in the frame 65, see Figs. 12 and 13. The opposite end oftheshaft I22 carries a worm wheel I23 which meshes with a worm I24 secured to the end of the counter-shaft 80 remote from the pinions I9, 82 as shown in 8 and 13, so that when the electric motor S'i is operating, the rotation of the shaft 85) is imparted through the worm gearing I24, I23, shaft I22, pinions IZI, 20, shaft H9, worm gearing H8, ii I, and shaft its to the .movable clutch member I01. When this clutch member It! is interlocked with the clutch member I03, by the clutch actuating servo-motor of Fig. 28, the pinion 7! is being power operated to impart drill feeding motion to the carrier 68 and spindle 66, through the shaft I02 and gears IOI, m0, but when the clutch members I03, iii! are disengaged, the carrier 58 and spindle 66 are free to be moved in either direction by the hand wheel 9'! secured to the shaft 96. It will also be apparent that with the clutch members I 03, I! thus disengaged, the pinion 'II is free to be operated by the piston 92 and rod 93 of drill withdrawing servo-motor of Fig. 27, and both the manual and automatic functioning of these servo-motors will be subsequently described more in'detail.

The clamp actuating mechanism which is carried by the drill unit 30 and which functions .to

automatically clamp the work orbeam 34 prior to.

drilling, is best illustrated in Figs. 6, 7, 10 and 11. While the same clamp actuating mechanism serves to interchangeably operate either of the three types of clamps shown in Figs, 1, 2 and 5, the.

pended from the frame 65; and linkage connecting the piston rod I30 of the servo-motorwith both of the slides I26. The clamp actuating servo-motor is shown in section in'Fig. 29,,and.

consists of a cylinder I3I having. a piston I32 secured to the rod I30, upper and lower ports. I33,

w I34 respectively for adrnitting and exhausting l fluid such as air under pressure to and from, the

cylinder I3I, and control valve mechanism for regulating the admission and exhausting of the air. The cylinder I3I is swingably supported uponthe pivot I35 and the outer end of the piston rod I30 is pivotally connected to the upper arm of a lever I36 which is secured to a cross shaft I31 journaled in a bracketsecured to the main frame 65. The lower arm of the. lever I36 is 'pivotallyattached to the upper end of a link I38, and the end of'the shaft I31 on the opposite side of the machine carries a similar arm likewise attached to another link I38. The lower ends of the links I38 are pivotally connected to the central arms of T-levers I39, corresponding ends of the cross-arms of which are pivotally attached to fixed brackets I40, and the opposite corresponding ends of the cross-arms of which are pivotally attached to the lowerends of links MI, as viewed in Fig. 7. The upper ends of the links I-il are pivotally connected to the slides I26, and these slides are recessed as shown for the reception of the T-levers I39, brackets I40 and links I4I. With this assemblage of elements, it will be apparent that when the piston I32 of the servo-motor I29 is moved, the rod. I will oscillate the cross shaft I37 through the lever I36, and the movement of the shaft I37 will be transmitted through the two sets of links I 38, T-levers I39 and links I4I to the slides I26 to cause these slides to move in the parallel guideways I28. This parallel movement of the slides- I25 will be imparted to the yoke I25 and from thence to the clamp arm42, to produce either a clamping or a clamp releasing efiect, dependent upon the direction of movement of the servo motor piston I32. The pivot I upon which the cylinder I3! is suspended, will permit the servomotor to swing freely as indicated in dot and dash lines in Fig. 7, when the lever I36 and shaft I9'l are oscillated.

As previously indicated, theperforating unit is angularly adjustably suspended from the yoke 3| the unit being swingable about a horizontal axis located near the center of gravity thereof. The mechanism for thus angularly displacing the unit 30 relative'to the suspension yoke 3I and for locking the same inadjusted position so as to permit drilling in various angular directions, is

tatably supported in bearings I43 attached to the frame 65, and having a polygonal head I441 formed integral therewith and adapted for cooperation with a socket wrench in order to turn the worm I42. The worm I42 meshes with a worm wheel I45 secured to a cross-shaft I46; which extends transversely through the unit 30 and is journaled in a bracket on the frame 65 thereof. Secured toeach end of the cross-shaft I46 is a spur pinion I41 and. each of these pinions meshes with a spur gear M8. The spur gears I48 are rotatably supported upon stub shafts I49 fixedly attached to the main frame 65, and are adapted to coact with the ends of the suspension yoke 3I through lugs I 50 formed'in-;

tegral with the gear peripheries. The common axis of the stubshafts I49 penetratesthe perforating unit 30 near the center of gravity thereof, and the loose coaction between the lugs I50.

and yoke 3|, permits the unit 30 to swing freely to. 'a small extent, at all times. It will be ap-; parent, that by rotating the worm I42 with the aid of a wrench applied to the head I44, rotation will be imparted through the worm wheel I45 and shaft I 46 to the pinions I 41, and these rotating-pinions I41 will roll along the peripheries of the fixed gears M8 until the rotation of the actuating worm I42 stops. The drillnnittil may thus be adjusted to any desired angular position relative to the suspension yoke ti and about the axis of the stub shafts M9, and the worm I42 coacting with the worm wheel I l-5 serves to effectively lock'the unit 36 in adjusted position, If so desired, a suitable gage for approximately determining the degree of angular adjustment, may be provided- From the preceding description, it will be noted that the improved perforating unit 3! is provided with three fluid pressure actuated servomotoranamiely the drill spindle balancing and withdrawing servo-motor shown in Fig, 27, the clamp actuating servo-motor of Fig. 29, and the-clutch actuating servo-motor illustrated in Fig. '28,. For convenience, these servo-motors will be designated as the balancing, clamp and clutch servomotors respectively. The admission and exhaust of compressed air to and from these servo-motors is controlled by an improved assemblage of valves which are shown in enlarged form in Figs. id to 26 inclusive, and the interconnection between these several control valves and the servo-motors is also illustrated in Figs. 6, 7, 8, 9, 11, 14 and 15. This assembly comprises three main piston valves lei, itZ, its and a 'pilot or actuating valve 55% slidable within the main valve 552. The main valve I5I controls the balancing servo-motor, and the main valve I53 controls the clutch servo-motor, While the main valve I52 and auxiliary valve i54 control the clampservo-motor. All of the main valves I55,

" I52, I53 are slidably mounted in a common valve casing I55 which is detachably secured to the upper portion of the main frame E5 of the unit 39, and a valve actuating rod l56 which is slidable longitudinally and parallel to the drill spindle axis, is. also slidably and rotatably supported in the casing E55 and frame $5. The single actuating rod E55 at times cooperates with all of the main valves Ifil, I52, I53, and while it would appear from the diagrams illustrated in Figs. 21 to 25 inclusive, that there are two rods I55, there is in fact only one such rod and the apparent duplication of this element in these diagrams, has been made merely for the sake of clearness.

The lower portion of the actuating rod 55 which coacts with the main frame 65 directly adjacent to the pinion H and clutch serv0-motor as shown in Fig. 8, is provided with a pair of vertically spaced collars i351, I53 having lateral projections which are, under certain conditions of operation, engageable with a fixed pin I 59 carried by the piston rod 93 of the balancing servomotor as clearly shown in Figs. 7 and 11. The collars I57, I53 may be adjusted to difierent positions along the rod lEi so as to change the time of contact with the pin I59, and it will be ap parent that when the drill spindle 66 is feeding the drill 4t forward, the pin I59 approaches and eventually engagesthe collar I5? to move the rod I56 upwardly, whereasreverse or withdrawal motion of the spindle 66 and drill is will even tually cause the pin I53 to engage the collar I58 and move the rod I55 downwardly. In addition to this action produced by the motion of the spindle 6t and drill ll) due to feeding of the drill by the motor 5?, and withdrawal thereof by the hand wheel ll'l, movement of the piston rod 9.3 by fluid pressure applied to the piston 92 will also cause engagement of the pin I55) with the collars I51, I58, and the rod I56 is furthermore manually shiftable and rotatable with the aid of a handle I68 secured thereto between the collar I57 and the valve casing 55 as shown in Fig. 16. The extreme upper end of the actuating rod I56 is provided with an element ltihaving spaced flanges E62, I63 and also having a series of three notches I64 therein which are engageable by a spring pressed latch I65 as illustrated in Fig. 13. The flanges H32, H53 are approximately semicircular in form as shown in Fig. 16, and the element I5! is locked to the red I56 by a nut I66.

One end of the balancing servo-motor control valve I5I is provided with an abutment collar I5? which, with the rod I58 in normal position, projects into the recess formed by the element flanges M2, M53 as shown in Figs. 16, 18, 21, 22, 23, 2d and 25, but the rod 556 may be rotated with the aid of the handle I66, as indicated in Fig. 16, to move the projections of the collars 551, E58 out of the path of travel of the rod pin H9. The collar it? is of less thickness than the distance between the flanges I52, I63 so as to permit relative movement of the valve I5I and rod I56, and the opposite end of the valve l'l is provided with an adjusting handle E68 for manually swinging this valve about its longitudinal axis through an angle of ninety degrees as indicated in Fig. 16, for horizontal disposition of the unit 39. The medial portion of the valve I5I adjacent to the handle IE8 is provided with 7 parallel annular grooves I69, I I6 connected by a transverse groove I'll, and a spring pressed latch I72 mounted in the casing I55 is adapted to coact with the grooves I59, I18 and with detents located at the intersections of the grooves its, lid with the groove Ill. The casing i555 is. provided with a T-shaped fluid pressure supply conduit I'lt which communicates with a supply pipe EM, and which also connects with an inlet or supply port for the valve WI. The valve 25% is provided with a longitudinal fluid passage HE and with a lateral passage I16 communicating with the passage H5, and is furthermore provided with a longitudinal passage I'Il' disposed below the passage Ilfi. These passages H5, H6, Eli are utilized when the valve 555 and its actuating lever I68 are positioned as shown in Figs. 16 and 18, and the unit 3% is to be operated with the drill ii) movable vertically. The valve casing I55 is also, provided with upper and lower con-.

duits H8, IlQ disposed adjacent to the valve passage I15, with a conduit E853 communicable with the passage lit, and with an exhaust conduit I8I. The conduits I18, I89 communicate. directly with the upper end of the cylinder 9B of the balancing servo-motor, and the conduit H8 is provided with an adjustable control valve I82 for controlling the speed of travel of the piston 92.

v The clamp control valve mechanism comprising the main valve E52 which is slidably supported by the casing I55 and the auxiliary valve I5 i slidably mounted within the main valve I52, is shownv in Figs. l6, 17, 2.1, 22, 23, 24 and 25. The upper end of the main valve IE2 is provided with a collar I83 having a lateral projection l 84 thereon which is of less width than the collar it? on the valve I5I and which, is likewise disposed in the recess formed between the rod flanges I62, I63. A handle I85 is formed integral with the collar I33, and. a fixed stop E8 65 secured to the casing I55, serves to limit the movement of the valve I52 and collar lBtaway from the casing I55., Th60llt61 end of the auxiliary valve I54 ispivotally attached to one end of a link I 81 the opposite endof which is-pivot'ally connected to the swinging 'end' of a lever arm E88, see Figs. 11, 13, 14 and 15. The lever arm $88 is secured to one end of a pivot shaft I89 and the swinging end or" a second lever arm Hit secured to. the oppo ite end of the pivot shaft 589 is pivotally connected to the end of the push button rod 58, see Figs. 12, 13, 14 and 15. It will thus be noted, thatwhen the push button 99 is pressed, the rod 98 will impart motion to the auxiliary valve I54 through the arm i913, pivot shaft iti arm I88, and lin I3l, so as to move the valve I54 within the main clamp control valve I52. The valve l 52 besides being slidable relative to the'casing E55, is also rotatable by means of the actuating handle, as indicated in Fig. 16, so as to throw thelprojection I36, out of the path of travel of the rod flanges I52, I63. The auxiliary valve .IM is a pilot valve for controlling the admission of compressed fiuid to and from the con fined space at the lower end of the valve I52, and has superimposed annular passages iQl, Idi which are alternately communicable with a longitudinal passage l93 formed in thevalve I52. The valve I 54 also has a central exhaust port I 574 Which connects with the lower annular passage I92 and with the atmosphere through the open end of the bore in which the valve E52 is slidablef The passage E93 oi the valve I52 connects the confined space at the lower end of this valve with upper and lower transverse ports I95, H95, the former of which extends entirely through the valve 552 and connects with the intermediate of three superimposed longitudinal passages I93,

I 98, I 99 formed on the side of the valve i5? opposite to the passage I 93. The conduits iss which communicate respectively with the upper and lower displacement chambers of the clamp servo-motor cylinder 53 l, are disposed respectively above and below the supply conduit H3 for the valve l52,.and two exhaust conduits 200 in the casing 455, are communicable through the passages ml, I with the conduits 533, I34 under certain conditions of operation. The delivery of compressed fluid from the conduit I13 to the valve IE2 is also regulable by means of an adjustable needle valve 29! mounted in the valve casing l '55, and the exhaust conduits 2% may likewise be rovided with how regulating valves located near the casing l55 as shown in Fig. 17.

The main clutch control valve I53 has an upper collar 2&2 provided With a lateral projection 203 which is constantly disposed in the recess between the flanges I62, I63 of the rod 56, and has an actuating handle 24 secured to the lower end thereof. This valve I53 is also provided with a series of three superimposed notches 205 which are alternately engageahle with one end of a double spring pressed latch 2&6 the opposite end of which is engageable with notches 201 formed in a plate 2138 secured to the valve casing I55. The casing of the latch 266 is fixedly attached to the swinging end of a lever 269 which is secured to one end of a pivot shaft 2H3 the opposite end. of which carries a second lever 2 I I, The swinging end of the lever L'II is pivotally connected to one of the parallel clamp moving slides I26 by means of a link H2, so that movement of the clamp yoke I25 and slides in will be imparted to the latch 265 through the link 2I2, lever 2i i, shaft 2 Ill and lever 209. The clutch control valve is thus movable both by the handle 2a: and rod I55, and by means 'of the latch 266, and the valve body has a series of three'superimposed longitudinal passages ZI3, 2M, 2I5 formed therein. The

fluid supply conduit ['53 is constantly communicable with the intermediate passage 2 M, and conduits 2 l E, 2 I I communicate with the opposite ends of the clutch servo-motor cylinder H4, and exhaust ports 2i 8, 25$ are communicable respectively with the conduits 2 I 5, 2 l l through the upper and lower passages 2 l 3, 2 I 5.

All of the foregoing description of the control valves, applies primarily when the drill is being operated vertically, and thevalve 555 must be rotated with the aid of the handles IE8 as indicated in Fig. 16, when horizontal drilling is to be effected. The valve lei is provided with a second set of passages 22%}, 22i, 222 as shown in Fig. 25, which function during horizontal drilling, these passages are communicable with the various conduits 5'53, H8, H9, I3, izli in the valve casing 555, to actuate the drill withdrawing rod horizontally. The valve E52 is likewise provided with special porting as shown in Fig. 2G, for supplying unrestricted quantities of to the lower face of this valve so as to produce quicker actuation thereof by the fluid pressure, but the precise mode of operation of the valves ii -i, E52 under these special circumstances, is relatively unimportant insofar as this invention is concerned. When operating the drill horizontally, is uinecessaryto counter-balance the weight of the drill spindle 55, as is done during vertical operation, and, the shifting of the valve 555 is primarily necessary in order to take care of this difierence. t will be apparent that when the piston 92 which is attached to the rod 93 is subjected to pressure on both sides, the rod 93 is free to. he moved in either direction by the hand wheel 9?, and the difference in pressure on the opposite piston faces, due to the area of the rod, serves to counter-balance the weight of the carriage 88 and spindle BE, and itis this counterhalancing which becomes Unnecessary during horizontal drilling. The porting of the valve 5! for horizontal drilling is therefore such that the opposite faces of the piston 92 areexposed to exhaust instead of to pressure, when hand wheel operation is desired.

As previously indicated, the improved portable perforating machine is susceptible of operation either by hand or automatically, at the will of the operator. The drill is rotatable by the electric motor ill, and the three servo-motors are adapted to automatically assist in the remaining operations and to facilitate hand com trol of said operations. One of these servo-mo tors actuates the clamping means; another of these servo-motors engages and releases the feeding clutch; and the remaining servo-motor func tions to balance the weight of the carrier and drill spindle $5, and provides additional power for withdrawing the spindle after a hole has been completed. Under ordinary conditions, these several operations will be automatically performed in proper sequence but provision is made for varying the timing of these several operations. in operation during vertical and horizontal drilling, and also permit either automatic or hand control of the clamp at the end of each operating cycle. .t will also be apparent that each of the several operations may at any time be controlled by hand, thus making the mechanism highly flexible in operation.

When ordinary automatic drilling is to be effected, the operation of the machine is substantiallyas follows. The unit 3d rests upon the legs 31, 38 which in .turn coact with the beam 34 These provisions take care of differences cylinder 9 l which is to be drilled, and the weight of the unit 36 is substantially balanced by the counter-weight 55 coacting with the flexible suspension means 32. The drill All is disposed vertically, and either of the vertical clamping mechanisms shown in Figs. 2 or 5, may be utilized, although the description will be directed to the form of clamping mechanism shown in Fig. 2. The clamp arms i=2, 4-3 are released, and the drill 49 is being rotated by the motor El through the gears l5, 19, 82, 33, 88, 8?, but with the feed clutch disengaged. At the time, the weight of the drill carrier i8 and spindle 66 is coun er-balanced by the admission of fluid under pressure to the opposite sides of the piston 92, so that the drill d6 can be moved up or down with the aid of the hand wheel Ql without undesirable resistance.

With the elements of the unit thus positioned, the operator manipulates the hoist 5? to counteract the unbalanced weight and to lift the unit 38 slightly away from the beam 33. The unit is then floating and can be readily moved from one location to another, being suspended from the supporting means 33 which is preferably provided with anti-friction bearings so as to permit convenient shifting of the unit. The operator may then manipulate the hand wheel 9i so as to move the rotating drill downwardly into a center punch mark or against any other mark point on the beam 34. The finding of the exact location of such marking point is additionally facilitated by having the machine pivotally supported upon a swivel EB and in the yoke St, the latter support being near the center of gravity of the unit 3%, and the lugs 50 permitting slight angular displacement of the unit relative to the yoke 52 After the drill point has been thus properly positioned with reference to a marking point, the operator may lower the unit 33 until it rests upon the legs 31?, 33 with the drill Mi rotating in the punch mark. By pressing the button 29 in the center of the hand wheel 9's, the automatic operation of the machine immediately proceeds. The pressing of the button 99 actuates the auxiliary clam control valve i5 5 and thereby causes shifting of the main clamp control valve i522 so as to close the clamp and draw the unit 38 into firm engagement with the beam with a pressure which greatly exceeds the drill pressure, thus locking the unit 38 to the beam. By providing this excessive clamping pressure, the torque reaction induced by the drill 58 is overcome and the lann'nations of the structure are clamped tightly together so as to prevent chips from becoming lodged between the laminations.

The last portion of the movement of the clamp actuating slide E26 causes the clutch control valve l53 to be actuated, to thereby engage the feed clutch and move the drill is downwardly.

The downward feed of the drill 38 continues until the drill point has penetrated the adjacent laminations of the beam .34, whereupon the upper element 15? on the rod E56 will be engaged by the pin we on the balance piston rod 93, the latter being moved upwarcuy as the drill All moves downwardly and vice versa. When the control rod l 55 is thus moved by the pin I58 it first actuates the valve ifil of the balance cylinder and thereby produces an unbalanced condition in the through the valve controlled pipe 18d, tending to withdraw the drill from the hole. Actual withdrawal is however resisted due to the fact that the feed clutch is still engaged, and the rod !56 will continue its movement until the clutchcontrol valve I53 is engaged and moved to release the feed. The drill lll is thereafter rapidly withdrawn from the hole, but the position of the drill unit 36 remains unchanged.

After the drill 49 has been withdrawn from a completed hole, the pin 5553 on the plunger rod $3 comes into engagement with the lower element H53, thus actuating the control rod I55 to release the clamping mechanism, and immedi ately thereafter causes the pressure within the balancing cylinder 9% and on the opposite sides of the piston 32 to be equalized, thus stopping the withdrawal movement of the drill 36 and placing the machine in condition for subsequent operation. It will be apparent that all of these several operations are performed automatically and in sequence upon manipulation of the button 99.

If the operator has made a mistake in the location of the hole after the machine has been placed in operation, he can stop further advance of the drill by manipulating the handle 160 on the control rod I56, to cause the elements 15?, i 58 to function exactly as if the release had been effected automatically. If the drill do is not cutting properly, the operator can release the feed at any time with the aid of the hand lever 2%, and since the spindle 66 is balanced, the

hand wheel 9i may be freely turned to move the drill out of the hole which is being formed, for inspection or otherwise, without disturbing the clamping mechanism or the position of the unit It is also possible, if the drill has been moved into position with the aid of the hand wheel 9'1, to resume the automatic drilling operation at any time with the aid of the feed control handle 2%.

If the laminations of the beam 34 are not perfectly flat, they are apt to buckle after the clamp has been released. It is therefore frequently desirable to clean away the chips before releasing the clamp, so as to prevent chips from becoming lodged between the laminations. By turning the handle I58 of the balancing valve l 5|, to condition the machine for horizontal drilling, all operations will follow the same sequence just described, and will be performed automatically, with the exception that the clamp need not be released at the end of the cycle, and instead may be released by the operator after cleaning or removal of the chips has been efiected. When the drill is to be repointed by grinding, the spindle may be moved downwardly with respect to'the unit 36} to make the spindle socket accessible for driving the drill d9 therefrom, without actuating the trip elements l5l, it, by turning the control rod l56 about its longitudinal axis to the position of the handle ltd indicated in dot and dash in Fig. 16.

It will thus be apparent that the handles 560, H58, H35 and 2M and the hand wheel 9], provide simple and highly effective means for manually controlling the various operations of the machine which are automatically eifected under ordinary conditions by merely pressing the button 99. The speed of rotation of the drill ill may be readily varied by substituting other gears for the speed reduction gears 82, 83 shown in Fig. 8, and the gears lZB, l2! may also be replaced by other gears in order to vary the amount of feed of the drill 50 for each revolution of the spindle 66. The operation of the machine is also susceptible of accurate control by means of the valve 82, needle valve 2lll,,and the control valves in the exhaust lines 200, and the latches coacting with the control valves l-5l, 52, 153 serve to.

definitely position these valves, for the various operating conditions. The latch I65 cooperating with the flanged element I6! of the control rod IE6, likewise serves to definitely position this rod, and the levers 269, 2! l, which are .actuated by one of the slides [280i the clamping mechanism, function during ordinary operation to shift the valve 53 through the latch 2% carried by the lever 2&9. i

From the foregoing description it will be apparent that the improved perforating machine is highly flexible in operation and functions automatically to clamp, drill and release in accordance with the various settings of the control valves represented diagrammatically in Figs. 21 to 26 inclusive. The fluid pressure actuated servo-motors effectively perform their several functions and their normal automatic actuation is at all times under hand control. The suspen sion mechansm for the perforating unit 353 permits universal adjustment thereof to cooperate with any portion of a beam 34, and the unit can be shifted throughout a considerable area. By providing interchangeable clamping means adapted for cooperation with any portionof a beam 34, the beam 3d may be definitely located and retained in position during the entire drilling thereof, thus eliminating necessity of subsequent reaming of the holes in order to insure alignment thereof through a number of laminations. The perforating unit may be operated to rapidly drill a succession of holes disposed at any angle and Will greatly reduce the cost of assembling laminated beam structures of various types. The releasable clamping mechanism shown in Fig. 2 permits convenient removal of the unit 36 from a beam structure of the type illustrated, and the various types of clamps may be readily applied to the unit to permit use thereof in conjunction with various portions of a complex beam structure.

It should be understood that it is not desired to limit the invention to the exact details of construction and to the precise mode of operation herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

t is claimed and desired to secure by Letters Patent:

1. In combination, a portable drill press, means carried by said press for supporting the weight thereof independently of the tool directly upon a piece of work to be drilled, a clamp arm carried by said drill press and cooperable with the work piece in opposition to said supporting means to clamp the work near the point of drilling, and means controllable by the clamping action to automatically actuate the drill spindle.

2. In combination, a drill press having means for supporting the weight thereof independently of the tool directly upon a piece of work to be drilled, a clamp arm carried by said drill press and cooperable with the work piece in opposition to said supporting means to clamp the work piece near the point of drilling, and means controllable by the movement of said clamp arm toward said supporting means to automatically advance the drill spindle.

3. In combination, a drill press having means for supporting the weight thereof independently of the tool directly upon a piece of work to be drilled, a clamp arm carried by said drill press and cooperable with the work piece in opposition to said supporting means to clamp the work piece near the point of drilling, and means controllable by the movement of the drill spindle away from the work for automatically moving said, clamp arm away from said supporting means.

.4. In combination, a drill press having means for supporting the weight thereof independently of the tool directly upon a piece of work to be drilled, a clamp arm carried by said drill press and cooperable with the work piece in opposition to said supporting means to clamp the work piece near the point of drilling, means controllableby the movement of said clamp arm toward said supporting means to automatically advance the drill spindle, and means controllable by the movement of the drill spindle away from the work for automatically moving said clamp arm away from said supporting means.

5. In combination, a portable drill press, means for rotating the drill spindle, work clamping means carried directly by said drill press, a fluid pressure actuated servo-motor for actuating said clamping means, another fluid pressure actuated servo-motor operable by the movement of said clamping means for controlling the feeding movement of the drill spindle, and still another fluid pressure actuated servo-motor for releasing said feed controlling servo-motor and for counterbalancing the weight of the drill spindle.

6. In combination, a portable drill press, a motor for rotating the drill spindle, work clamping means carried directly by said drill press, a fluid pressure actuated servo-motor for actuating said clamping means, another fluid pressure actuated servo-motor operable by the movement of said clamping means for controlling the feeding movement of the drill spindle, and still another fluid pressure actuatedservo-motor for releasing said feed controlling servo-motor and for subsequently withdrawing and finally counter-balancing the weight of the drill spindle, said servo-motors being adapted to function while said motor continues to rotate the drill spindle.

7. In combination, a portable drill press, means for movably suspending said drill press, means carried by said drill press and operable independently of the drill to clamp the opposite sides of a piece of work adjacent to the zone of action of the drill, means for supporting the drill press from said suspending means to permit movement of the drill in various angular directions, and means controllable by said clamping means for effecting automatic advancement of the drill ir respective of the selected angle at which drilling is being effected.

8. In combination, a portable drill press comprising a drill spindle and a motor for driving said spindle, suspension means coacting with said drill press near the center of gravity thereof, self-locking means for effecting angular adjustment of said drill press relative to said suspension means, work clamping means carried by said drill press and operable independently of the drill to support the press, and means controllable by said clamping means for effecting axial movement of said spindle.

9. In combination, a portable drill press comprising adrill spindle and means for driving the same, means for effecting angular displacement of said drill press bodily about an axis and for automatically locking the same in angularly adjusted position, and independent means for effecting vertical and horizontal bodily displacement of the drill press.

10. In combination, a portable drill press having an axially movable spindle,.means for rotating said spindle, a fluid pressure actuated clutch actuating servo-motor for controlling the movement of said spindle along its axis, means for arresting said movement andfor reversing the direction of advancement of said spindle at a predetermined moment, and common means for controlling said servo-motor and said reversing means.

11. In combination, a portable drill press having an axially movable rotary spindle, means for rotating said spindle, a fluid pressure actuated clutch actuating servo-motor for controlling the axial advancement of said spindle, a fluid pressure actuated servo-motor functioning independently of said clutch actuating servo-motor to arrest and reverse the direction of advancement of said spindle, and independent manually operable means for axially advancing said spindle in either direction.

12. In combination, a portable drill press having an axially movable drill spindle, a fluid pressure actuated clutch actuating servo-motor having a plunger for controlling the axial advancement of said spindle, means for establishing balanced fluid pressures upon said spindle, and manually operable means for moving said spindle and said plunger when the pressures have been thus balanced,

13. In combination, a drill press having means for supporting the same independently of the tool directly against a piece of work to be drilled, a clamp arm carried solely by said drill press and cooperable with the work piece in direct opposition to said supporting means to clamp the Work piece near the point of d illing, and means controllable by the movement of the drill spindle relative to the work for automatically moving said clamp arm.

14. In combination, a portable drill press having a rotary drill spindle, work clamping means carried directly by the drill press and cooperable with the work adjacent to the axis of movement of said spin-dle, a servo-motor for automatically actuating said clamping means in response to movement of said spindle, a clutch actuating servo-motor operable to control the feeding movement of said spindle, and another servomotor for releasing said clutch actuating servomotor and for Withdrawing said spindle from the Work.

15. In combination, a portable drill press having a rotary drill spindle, work clamping means carried directly by the drill press and cooperable with the Work adjacentto the axis of movement of said spindle, a servo-motor for automatically actuating said clamping means in response to movement of said spindle, a clutch actuating servo-motor operable to control the feeding movement of said spindle, and another servomotor for releasing said clutch operating servomotor and for successively withdrawing said spindle from the work and counterbalancing the Weight thereof.

16. In combination, a portable drill press having an axially movable drill spindle, a fluid pressure actuated clutch actuating servo-motor having a plunger for controlling the axial advancement of said spindle, a fluid pressure actuated servo-motor for releasing said clutch actuating servo-motor and for subsequently withdrawing and finally counterbalancing the weight of said spindle, and common control means for effecting actuation of said servo-motors.

KARL I-I. ANDREN. 

